Pressure operated switch



May 3, 1949. l. E. M CABE PRESSURE OPERATED SWITCH 2 Sheds-Sheet 1 Filed Dec. 2, 1944 INVENTOR.

IRA E. M c055 5% Arrow BY M FIB.Z

rMuvM/mmm May 3, 1949. E. McCABE PRESSURE OPERATED SWITCH 2 Sheets-Sheet 2 Filed Dec. 2, 1944 FIE 4 INVENTOR.

/RA 5. M CABE Mil" ATTORN Patented May 3, 1949 UNITED STATES PATENT OFFICE 11 Claims.

The present invention relates to improvements in pressure recording devices and more particularly to such devices used in conjunction with a radio transmitter whereby a radio signal emitted thereby may be intermittently interrupted in accordance with pressure changes for indicating change in altitude.

Among the objects of the present invention is to provide a novel pressure recording mechanism which is of simplified construction, positive in its operation, and readily calibrated for use in conjunction with a radio transmitter adapted to be sent aloft by a balloon or the like for recording wind direction and velocity at various altitudes which the balloon may attain.

Another object of the present invention is to provide a novel pressure sensitive mechanism for recording changes in pressure and which, through the medium of suitable mechanism, is adapted to actuate a switch of a radio transmitter circuit for interrupting the radio signal in accordance with predetermined pressure changes in order that altitudes may be easily and readily recorded.

More particularly, the invention comprehends the idea of providing pressure responsive means in combination with a magnetically operated switch with suitable interconnecting mechanism for intermittently and successively operating the switch to control the emission of a radio signal of a radio transmitter.

Still a further object of the present invention is to provide a device of the type immediately hereinabove described in which adjustments may be easily and readily made in calibrating the instrument to compensate for manufacturing variances which may exist as between various pressure responsive means.

Still another object of the present invention is to provide a pressure recording device of the type herein under consideration in which the interconnecting mechanism between the pressure responsive means and the switch embodies clutch mechanism of the intermittent actuating type which in its nonoperative position permits freedom of movement of certain of the parts of the interconnecting mechanism to facilitate calibrating the device with a master barometer, but which clutch mechanism in its operative position is responsive to pressure changes for intermittently actuating a switch member for interrupting the radio circuit in which the same is incorporated.

As another object of the present invention, a device made in accordance therewith contemplates the provision of a lost-motion connection between certain elements of the means interconnecting the pressure responsive and switch means, whereby certain elements of the interconnecting means are successively held in pressure recorded positions without returning to prior pressure recorded positions even though the balloon to which the same may be attached descends through an altitude previously recorded.

Another object of the present invention is to provide a device of the type described in which the clutch mechanism is constructed and arranged for holding the switch actuating member in disassociated relation to either the switch or the actuating mechanism therefor to prevent injury to the switch and to eliminate the possibility of a closed switch draining the life of the battery constituting the source of electrical energy for the radio transmitter. Such improved construction also has the further advantage of providing for the free and unrestricted movement of the pressure responsive device and mechanism interconnected therewith so as to prevent injury thereto during its transportation from place to place.

The invention also has the further object of providing a novel clutching mechanism which, in addition to the functions hereinabove set forth, is adapted to engage a clutch element of the interconnecting means so as to position the pressure recording scale associated with the interconnecting means in predetermined position for ready recording so that the operator may definitely know the next successive altitude attained by the balloon upon receiving the first signal from the device.

Other objects, features, capabilities and advantages are comprehended by the invention, as will later appear and as are inherently possessed thereby.

Referring to the drawings Figure 1 is a plan view of a pressure recording device made in accordance with the present invention;

Figure 2 is a view in cross section of the device shown in Figure 1 and disclosing the operating mechanism therefor in elevation;

Figure 3 is a detached view partly in section and partly in elevation of certain of the operating parts of the mechanism shown in Figures 1 and 2;

Figure 4 is an enlarged detached view taken in the plane represented by line A-A of Figure 3 of the drawings and showing the elements disclosed in Figure 3 in certain operative relation to one another;

Figure 5 is a view similar to Figure 4 of the drawings disclosing the elements in another operative position with respect to one another;

Figure 6 is a view similar to Figures 4 and 5 of the drawings showing the operating mechanism in a position intermediate those positions as represented in Figures 4 and 5;

Figure 7 is a view in elevation of a switch used in the assembly shown in Figures 1 and 2 of the drawings;

Figure 8 is a detached plan view of certain of the operating mechanism for the device disclosed in Figures 1-6, inclusive;

Figure 9 is a fragmentary View in section through the operating mechanism shown in Figure 8 of the drawings;

Figure 10 is a view of an implement or tool used in connection with certain adjustments which are made in the device as shown on the drawings; and

Figure 11 is a fragmentary sectional view showing the clutch elements in engagement.

Referring now more in detail to the drawings, a device made in accordance with the present invention is disclosed as comprising a pressure responsive means 2, a switch mechanism 4, and suitable means 6 interconnecting the same whereby the switch is operated in accordance with predetermined pressure changes of the pressure sensitive mechanism 2. The device as shown is constructed particularly for use in conjunction with a radio transmitter which in assembled relation is carried aloft by, a free balloon for determining by radio direction finding equipment, wind direction and velocities at different altitudes.

In the present form of the device, the mechanism generally described above is attached or mounted to a panel B suitably mounted within a container I O which is so constructed as to be readily assembled with the radio transmitter and carried aloft as above described. The mechanism is secured to the panel 8 through the medium of a bracket I2 connected thereto by rivets I5 or the like, said bracket I2 having a leg I 4 serving as a support for .the pressure responsive means 2, an intermediate curved portion I6, and having at its other end the spaced walls or fingers I8 and serving as a support for certain of the mechanism to be hereinafter more fully described and which walls are secured in rigid relationship to one another by means of a pillar post 22.

Mounted between the Spring fingers 24 attached to the bracket I2, and extending through the opening 28 of partition 8, is a switch 28 of the general design disclosed in the McCabe Patent No. 2,325,785 and more particularly disclosed in Figure 7. The switch 28 is of the mercury type including a hermetically sealed tube 30 having a stationary electrode 32 which has a lower tubular portion 34 extending into a pool of mercury .35 normally provided within the lower tip of the tube 39. The switch is further provided with a movable electrode 38 having acontact 40 adapted to engage a film of mercury at or adjacent the tubular portion 34 for closing a circuit through the leads 42 and 44 which in the present instance are connected to the plug 46 mounted in the casing ID and which is adapted to complete a circuit through theradio transmitter with which this instrument is associated during normal use for providing a radio signal when the electrodes 32 and 38 are in closed position. The switch is further provided with the abutment member 48 against which the electrode 38 engages in its open position. As clearly set forth in the ill McCabe patent above identified, the tubular portion 34 of the electrode 32 provides a meniscus of mercury to assure completion of a circuit through the switch even though the pool of mercury 36 is displaced from its normal position, which in the present instance is of importance inasmuch as the balloon may be subjected to a considerable amount of swinging movement during its ascent.

The movable contact element 38 is provided with an armature 50 disposed adjacent the wall of the tube 30 and adapted to be positioned so as to come within the field of a body 52 of magnetized material secured as by means of a screw 54 adjacent the end of a switch actuating member 56. This actuating member including the magnet 52 comprises adjacently disposed arm elements 58 and 60 mounted for relative pivotal movement with respect to one another upon a hub 62 secured to the shaft 64 mounted in the opposed walls I8 and .20 of the bracket. The arm element 58 which carries the body 52 of magnetized material extends beyond the pivot shaft 64 and is provided with the laterally disposed leg 66 adjacent its other end. The arm element 60 is provided at one end with abutment shoulders 68 and 10 to be hereinafter more particularly described and at its other end with the transversely or laterally extending leg or flange 72 in opposed relation to the leg or flange 66 of the arm element 58. Interposed between the legs or flanges I2 and 66 and held against displacement by the portions such as H struck out from such legs or flanges is a coil spring 16 normally urging the said elements 58 and 60 apart For adjusting the relative position of the arm elements 58 and 60, there is provided a screw I8 extending through a suitable opening in the leg 66 and which has threaded engagement with the leg or flange 12 whereby the positioning of the body 52 of magnetized material with respect to the switch 28 can be readily secured for proper operation of said switch.

The pressure responsive means 2 is of the aneroid capsule type which may comprise one or more circular containers such as but which in the present embodiment consists of two formed to provide an exhausted chamber defined on opposite sides by circular distortable walls subject to expansion and contraction by changes in pressure.

The pressure unit according to the present disclosure is secured, through the medium of the threaded shaft 82, to the leg l4 by the nuts 84 which shaft is connected to the outer wall of the first pressure element, the entire unit being adjustably mounted for positioning the pressure recording device as will be more fully explained hereinafter. The two units of the present embodiment are connected through the element B6 secured to the adjacently disposed inner walls of the said pressure elements. Pivotally connected as at 92 to the front wall 88 of the second pressure element is an actuating arm 90 which is provided with an elongated slot 94 adjacent its outer end operatively positioned within an annular roove 96 of a pin 88 secured to the face of the disc I00. The elongated slot 94 is provided with an enlarged end portion I02 adapted to fit over the pin in assembling the operating parts of the interconnecting means 8.

The disc I00 is mounted upon the shaft I04 journaled in the plates I8 and 20 of the bracket I2. As more particularly disclosed 'in Figures .8-10 of the drawings, the pin 98 is provided with 7.5 a threaded shank I06 extending through the ec centric slot I08 of a toothed element H0 and an aligned elongated slot H4 provided in the disc I00, the said pin 98 having the shoulder I I2 abutting the element I I0 for holding the element H0 and the disc I00 in associated relation to one another. The pin 98 is held in assembled relation with the member [I0 and I 00 through the medium of the nut H6 and the lock washer II8.

-As will be noted, the pin 98 is formed with the hub H9 fitting the slot Hi8. Thus by loosening the nut I I E and rotating element I I0 with respect to the disc I00, the pin 98 may be adjusted radially with respect to the shaft I04 to change the effective lever-arm for rotating disc I00. The nut I It may then be tightened to hold pin 98 in its adjusted position.

Under normal operations of the mechanism hereinabove described, deflection of the diaphragm upon a decrease in atmospheric pressure causes rotation of disc I00 in a counterclockwise direction as viewed in Figure 1 of the drawings. In order to provide proper seating relation between the pin 98 and its actuating arm 90, a yoke I20 is provided which has seating relation in the groove I22 of pin 98 intermediate its ends, one of the other ends thereof being seated in a groove formed in the shaft Hi4 and the other end being provided with a hook portion I24 to which one end of a coil spring I26 is attached, the other end of the coil spring being attached to the pivot pin 92.

In order to adjust the toothed element I III with respect to the disc I00, a special tool is provided as shown in Figure of the drawings, the same being formed with a projection I 28 at one end thereof adapted to be received in the opening I36 of the disc element I00 and adjacent which projection I28 is a tooth gear I32 meshing with the teeth formed at the periphery of the element IIO whereby, upon rotation of the tool, relative movement of element III! with the disc I09 is accomplished upon loosening of the nut I I6. As previously described, adjustment of element H0 is effective in adjusting pin 98 radially with respect to shaft I04 in order to compensate for differences in the deflection or distortion of the pressure responsive means occurring upon decreasing atmospheric pressures which may be experienced in different units even though constructed for similar deflection over the same pressure operating range,

In accomplishing the adjustment immediately above described, the tool shown in Figure 10 of the drawings is provided at its other end with an enlarged hub I3 3 formed with a non-circular recess I36 adapted to correspond to the shape of and receive the nut I I8 when introduced through the opening I38 of partition member 8. After the pin adjustment has been accomplished, the nut I I6 may again be tightened to secure proper operation of the pressure responsive device as compared to master instruments used in calibrating the same.

pressure is readilly translated in terms of altitude as the device is used in securing wind direction and velocities. It is to be noted that upon a decrease in pressure as the altitude increases, thediaphragm 88 is moved or expanded outwardly to operate disc I00 so that the scale as shown provides for a graduated decrease in millibar pressure from the position as indicated by the pointer I46 to the lower-most part of the scale at the bottom portion of the disc I00 as shown in Figure 1 of the drawings. Accordingly, the instrument as shown in Figure 1 of the drawings is illustrative of the relative position of the elements at the time when readings are to be initiated and the balloon sent aloft.

It will, therefore, be clearly apparent that recordable pressure changes, due to a decrease in atmospheric pressures, are operative to rotate disc Int counterclockwise as shown in Figure l of the drawings successively from tooth to tooth relative to the pawl I42. Each recordable change of pressure causes a tooth on the disc I00 to displace the pawl I42 to rotate the switch actuating member 50 about its pivot point, thereby moving the magnetic field of the magnet 52 away from armature iii? and allowing electrode 38, under the impuise of its spring element I48, to move into engagement with the abutment 48 and to break the circuit so as to interrupt the radio signal which is then recorded by the radio direction finding equipment. Operation of the magnet 52 is effected through the medium of magnetic attraction for the armature 5b of the switch, thus maintaining the switch arm in its operative position to close the switch and to maintain engaging relation of the pawl I42 with the ratchet teeth I40. Each recordable change in pressure in accordance with the calibration of the instrument is indicative of a certain increase in altitude. Accordingly, with such recorded information with respect to altitude and other information with respect to wind direction and velocity observations which are simultaneously taken, wind conditions at each of the altitudes can be properly recorded.

The present mechanism further includes clutch control means for engaging and disengaging the switch actuating member 55 from the operating disc Hill and for initially setting the disc 1% in a predetermined operative position. Such means essentially includes a cam shaft I50 journalled in the side walls is and 20, as more clearly shown in Figure 3 of the drawings, which cam shaft is operated from on to off positions, as shown in Figure 1, by the laterally extending handle portion I52. This cam shaft is provided with a cam surface I54 which is adapted to engage an abutment shoulder 58 of the switch actuating arm 60 when the device is in the off position, as shown in Figure 4, to hold said arm substantially immovable in a position between the cam and pillar post 22, the latter serving as an abutment for the projection I0 extending from the switch actuating arm Gil. In this position the arm 60 prevents the body of magnetized material. 52 from engaging the receptacle or container 3%] of the switch and thus prevents closing of the switch until ready for use as well as removing the danger of injury to the switch in any way which might otherwise occur by the magnet striking it when the device is handled before being used. At the same time the pawl I42 is disengaged from the teeth hit of the disc I00 to release the disc from its interconnected relation with the switch actuating member, permitting unrestrained movement of the pressure means 2 upon subsequent changes in pressure. When the pawl is disengaged from the teeth of the disc, the device may be readily calibrated through adjustments of the shown in Figure 3. extends beyond the bearing I10 and is provided ated elements.

nuts. and pin 93 so that thescale I44 mayprop- 'erly indicate the initial pressure to which the device is adjusted and so that subsequent recordations are in accordance with the scale readings. In order to maintain the cam shaft in either the 'on' or oil positions when so rotated, the same is formed with a fiat section I56 engaged by a spring component I58 of a spring element I60.

To support the spring in position the element I60 is provided with depending leg portions I52 and I64, both of which are provided with openings such as I56 embracing eccentric bearings I68 and III) disposed on both sides of the flat I56, as The top leg of element I60 with an elongated slot I12 adapted to embrace 2. lug I I4 struck out from the wall I8 to assure proper positioning of the spring element and its alignment at all times with respect to'the associtension thus constantly engages the cam shaft to .hold it in the position it assumes upon movement of the handle i52 to either ofi or on position.

In order to assure that the first altitude recorded by the device is definitely known, the lower leg I62 of the spring element I8!) is formed with a laterally extending pawl I15, which upon movement of the shaft I5!) from its off to its "on position, engages a tooth of the disc I00 to rotate the disc so that thelpawl I42 will assume a position one tooth lower on the scale when thus operatively associated therewith than it would normally do if movement of the disc did not accompany such rotation of handle I52 and the shaft I50. By noting the reading of the dial and recording it the operator may readily determine from the first signal received after the instrument is sent aloft the exact altitude at which it is recorded. The upper leg I54 oi the spring element I88 serves to maintain the pawl I16 in its proper relative position with the teeth of disc I08 so as to engage the disc and move the same with each movement of handle I52 from oil to on position. As heretofore described, the lug I14, extending into slot I12 of leg I64, assures of this alignment.

During movement of the device to higher altitudes, the switch actuating arm 58 is intermittently moved out of operative association with the switch to interrupt the radio circuit and to thereby audibly indicate to the operator such intervals of increase in altitude that are commensurate with the pressure changes of the pressure responsive means. During this operation,

the disc Hill and the switch actuating member 58 are interlocked by means of the pawl I42 engaging in the teeth Mil of the disc I00. The relationship of pawl I42 to the teeth in the disc is such asto permit counter-clockwise rotation of the disc,

upon decreasing atmospheric pressure to intermittently actuate the pawl and rock the switch member 55 and thus the magnet 52, and to also result in a locking arrangement between them 'to prevent clockwise rotation of the disc. By virtue of the elongated slot 9a in the actuating arm 90, the lost motion connection is provided between .the pressure responsive means and the disc I00 so that with the disc locked against clockwise movement the pressure responsive means may not be retarded in its contractual movement, which takes place upon increasing atmospheric pressures. Consequently, although the balloon may reach any given altitude as recorded by an interruption in the radio signal and thereafter descend to an altitude previously recorded, no signal will again be transmitted-until the altitude next intended to be recorded, higher than the last, is reached. That is to say, increases in altitude are successively recorded but because of the lostmoticn connection these hereinabove described lower recordations are impossible and such preschanges due to decrease in altitude which may cause movement of the diaphragm 88 are not efiective in moving disc I00 to interrupt the radio signal.

It will be apparent that after an operation and the device is again made ready for use, the dial maybe reset to its initial position by turning the cam shaft I50 to off position at which time such release of the disc causes spring I26 to return the disc to its initial position automatically.

By actual tests it has been found that in a device constructed in accordance with this disclosure in which suitable materials have been used accuracy within 1-2 millibars has been obtained at 50 millibar intervals based on absolute pressure readings. Furthermore, repeated use of the same device has been possible without the need of field adjustment to retain the same degree of accuracy and throughout a temperature range of 50 to l0 C.

While I have herein described and upon the drawings shown an illustrative embodiment of the invention, it is to be understood that the invention is not limited thereto but may comprehend other constructions, arrangements of parts, details and features without departing from the spirit of the invention,

holding action on the operating means when the clutch elements are in engagement to prevent return of the operating means to a prior pressure recorded position, and said operating means having a lost motion connection between said pressure responsive means and said actuating means for permitting said pressure responsive means to move through any of the prior pressure recorded positions.

2. A pressure recording device as defined by claim 1, additionally including control means for manually engaging and disengaging said clutch elements.

3. A pressure recording device as defined by claim 1, additionally including control means for manually engaging and disengaging said clutch elements, said control means having a member operable upon actuation of the control means for presetting said operating means.

4. A pressure recording device as defined by claim 1, additionally including control means for manually engaging and-disengaging said clutch elements, said control means in one position of adjustment locating and holding'the switch actuadjustment locating and holding the switch actuating means in inoperative position, and a member actuated by the control means into engagement with one of the clutch elementsfor setting said clutch elements in predetermined relation to one another when the device is initially set for operation.

6. A pressure recording device comprising a magnetically operated switch adapted to be included in an electrical circuit, a switch actuating member having a pawl, pressure responsive means including a diaphragm expansible upon a decrease in pressure, means for operating said actuating means in accordance with the expansion of said diaphragm due to predetermined successive recordable reductions in pressure, said operating means comprising a rotatable member having a plurality of peripheral teeth forming a ratchet engageable by said pawl, a pin spaced with respect to the axis of rotation of said member, and an operating bar connected to said diaphragm and operating through said pin to rotate said member for intermittently actuating said switch actuating member through said pawl and ratchet.

7. A pressure recording device as defined by claim 6, wherein said bar is provided with an elongated slot embracin said pin and forming a lost motion connection therebetween, said connection being constructed and arranged whereby the bar is operative to rotate said rotatable member only upon expansion of the diaphragm as a result of decreasing pressures.

8. A pressure recording device as defined by claim 6, wherein means are provided for adjustably positioning said pin with respect to the axis of rotation of said member.

9. A pressure recording device comprising a magnetically operated switch adapted to be included in an electrical circuit, a switch actuating member having a pawl, pressure responsive means including a diaphragm expansible upon a decrease in pressure, means for operating said actuating means in accordance with the expansion of said diaphragm due to predetermined successive recordable reductions in pressure, said operating means comprising a rotatable member having a plurality of peripheral teeth forming a ratchet engageable by said pawl, a pin spaced with respect to the axis of rotation of said member, an operating bar connected to said diaphragm and operating through said pin to rotate said member for intermittently actuating said switch actuating member through said pawl and ratchet, said bar being provided with an elongated slot embracing said pin and forming a lost motion connection therebetween, said connection being constructed and arranged whereby the bar is operative to rotate the member only upon expansion of the diaphragm as a result of decreasing pressures, and control means including a cam shaft rotatable to engage and disengage said pawl from said ratchet teeth, said control means in one position of adjustment locating and holding the switch actuating member in inoperative position.

10. A pressure recording device as defined by claim 9, wherein said control means has spring means associated therewith for yieldingly holding said shaft in its operative and inoperative positions.

11, A pressure recording device as defined by claim 9, additionally including a member actuated by said control means into engagement with a tooth of said ratchet for positioning said ratchet in predetermined position with respect to said pawl on the switch actuating member as said control means is moved from inoperative to operative positions.

IRA E. McCABE,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,283,919 Diamond et al. May 26, 1942 2,333,263 McCabe Nov. 2, 1943 2,347,160 Wallace Apr. 18, 1944 

